1. Field of the Invention
The present invention relates to communication terminals provided with close-proximity communication systems and contactless power transmission systems.
2. Description of the Related Art
NFC (Near-Field Communication), RFID (Radio Frequency Identification), and such systems are examples of close-proximity communication systems. The RFID system is a close-proximity communication system that uses magnetic coupling between a R/W-side coil and a tag-side coil, and is used for monetary transactions, authentication, and the like.
Qi (registered trademark), meanwhile, is a power transmission system that uses magnetic coupling, serving as an example of a contactless power transmission system. This power transmission system can transmit power without contact, using magnetic coupling between a power transmitting apparatus-side coil and a communication terminal-side coil.
Japanese Unexamined Patent Application Publication No. 2009-247124 discloses a communication terminal provided with a close-proximity communication system and a contactless power transmission system.
Extensive space cannot be secured within the housing of a small-sized communication terminal, and as a result, it is impossible to avoid disposing a coil for close-proximity communication and a coil for power transmission near each other. There is thus a risk that the coil for close-proximity communication and the coil for power transmission will magnetically couple during close-proximity communication or during power transmission. In such a case, the resonant frequency of the close-proximity communication circuit or the power transmission circuit will change, resulting in a problem that desired electrical characteristics cannot be obtained for the communication terminal.